The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the inventors hereof, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted to be prior art against the present disclosure.
In a wireless MIMO system, beamforming technique is used to control the directionality of the transmission and reception of radio signals. For example, the phase and relative amplitude of a radio signal can be controlled at each transmitter to create a pattern of constructive and destructive interference in the wavefront. At the receiver, information from different sensors is combined in a way where the expected pattern of radiation can be observed.
In 802.11n/a/g standards, which uses OFDM modulation, there is no information in the packet preamble that may allow the receiver to directly identify if the received OFDM packet is beamformed or not. Identification of whether the received packet is beamformed or not can help the receiver in switching to the respective packet decoding algorithm that performs better for beamformed packets, but may not perform as well for non-beamformed packets.